Ventrally emigrating neural tube cells migrate into the developing vestibulocochlear nerve and otic vesicle

Virtually all cell types in the inner ear develop from the cells of the otic vesicle. The otic vesicle is formed by the invagination of non-neural ectodermal cells known as the otic placode. We investigated whether a recently described cell population, originating from the ventral part of the hindbrain neural tube known as the ventrally emigrating neural tube (VENT) cells, also contributes cells to the otic vesicle. The ventral hindbrain neural tube cells were labeled with the fluorescent vital dye DiI or replication-deficient retroviruses containing the LacZ gene in chick embryos on embryonic day 2, after the emigration of neural crest from this region. One day later, the labeled cells were detected only in the hindbrain neural tube. Shortly thereafter, the labeled cells began to appear in the eighth (vestibulocochlear) cranial nerve and otic vesicle. From embryonic day 3.5-5, the labeled cells were detected in the major derivatives of the otic vesicle, i.e. the endolymphatic duct, semicircular canals, utricle, saccule, cochlea, and vestibulocochlear ganglion. That the emigrated cells originated from the ventral part of the hindbrain neural tube was confirmed by focal application of DiI impregnated filter paper and with quail chimeras. It is concluded that, in addition to the otic placode cells, the otic vesicle also contains the ventrally emigrating neural tube cells, and that both cell populations contribute to the structures and cell types in the inner ear. It is well known that inductive signals from the hindbrain are required for the morphogenesis of the inner ear. The migration of the hindbrain neural tube cells into the otic vesicle raises the possibility that the inductive effect of the hindbrain might be mediated, at least in part, by the ventrally emigrating neural tube cells and that, therefore, a mechanism exists that involves cells rather than diffusible molecules only.     

Myocardial sestamibi single-photon emission tomography: Variations in reference values with gender, age and rest versus stress?

Reference data files support the evaluation of myocardial perfusion single-photon emission tomography (SPET). The aim of this study was to create a large reference data base for technetium-99m sestamibi SPET, age and gender matched to the general patient population. One hundred and twenty-eight healthy volunteers (76 males and 52 females) with a likelihood of coronary artery disease of less than 5% underwent rest and maximal exercise^99mTc-sestamibi SPET with a 2-day protocol and 180° elliptical rotation. The normalized activity values of^99mTc-sestamibi in the inferior wall differed significantly between men and women. Age variations were found for men in the anterior wall. Normalized activity values in all four walls were strikingly similar during rest and stress. Our results suggest that the use of reference files in^99mTc-sestamibi SPET requires a gender- and, for males, possibly an age-matched reference population. Different reference files at rest and during stress might not be necessary.     

Aetiology of neonatal septicaemia in Qatif, Saudi Arabia

Neonatal septicaemia (NNS) is a major cause of neonatal morbidity and mortality. Neonatal septicaemia was studied to determine the incidence, common bacterial aetiology and antibiotic susceptibility in Qatif Central Hospital, Saudi Arabia. Of 1,797 babies admitted into the unit over a 3 year period, 144 (8.0%) had documented neonatal septicaemia consisting of 94 (65%) late onset and 50 (35%) early onset septicaemia. The incidence was 8.2/1000 of the total live births in the hospital.

Gram negative bacteria were encountered in 66.2%, gram positive bacteria in 29.2% and Candida albicans in 4.4% of the case. Klebsiella spp., E. coli, and Pseudomonas accounted for 81.8 % of the gram negative while Staphylococcus epidermidis, Staphylococcus aureus and group B Beta haemolytic Streptococcus accounted for 73.9% of the gram positive bacteria.

Most of Gram negative bacteria had a high sensitivity to Aminoglycosides and third generation Cephalosporins. Coagulase negative staphylococci were frequently resistant to most antibiotics but always sensitive to Vancomycin. The overall mortality rate was 18.7%.     

Medium-Depth Chemical Peels in the Treatment of Acne Scars in Dark-Skinned Individuals

BACKGROUND: Multiple modalities are available for treating acne scars, one of which is chemical peeling. OBJECTIVE: To evaluate the efficacy of medium-depth peels in the treatment of acne scars. METHODS: A total of 15 patients (14 women and 1 man) were seen between November 1998 and March 2000. A medium-depth chemical peel was performed. The peel was performed using a combination of Jessner's solution followed by the application of 35% trichloroacetic acid (TCA). The mean age of patients who entered the study was 28 years. A total of 42 peeling sessions were performed: 13 patients had the full three-session regiment, 1 patient had two sessions, and 1 had only one session. RESULTS: Patients in our study had two forms of acne scars, the atrophic saucer or crater-like form and the pitted (ice-pick) form. Improvement occurred in all except one of our patients. Significant improvement (greater than 75% clearance of lesions) occurred in 1 patient (6.6%), moderate improvement (51-75% clearance) in 8 patients (53.3%), mild improvement (26-50% clearance) in 4 patients (26.6%), minimal improvement (1-25% clearance) in 1 patient (6.6%), and no response in 1 patient (6.6%). All patients had different combinations of the above two forms. Four patients (26.6%) had mainly pitted scars and deep atrophic scars. The clinical response in those patients was moderate, mild, minimal, and no response, respectively. The remainder of our patients had mainly atrophic scars of moderate depth. Nine patients (73.4%) suffered from transient postinflammatory hyperpigmentation. In two of them it was preceded by erythema that lasted for more than 1 month. All patients were free of noticeable pigmentation 3 months after the final peel. Patients in whom hyperpigmentation did not develop were of light brown complexion. CONCLUSION: We conclude that medium-depth chemical peel is a safe and effective method of treating acne scars even in patients with dark complexion.     

Comparing health system performance assessment and management approaches in the Netherlands and Ontario,Canada

Background  

Given the proliferation and the growing complexity of performance measurement initiatives in many health systems, the Netherlands and Ontario, Canada expressed interests in cross-national comparisons in an effort to promote knowledge transfer and best practise. To support this cross-national learning, a study was undertaken to compare health system performance approaches in The Netherlands with Ontario, Canada.